Angry Wrentit ?

Yesterday this Wrentit seemed to strike an angry pose as it stared out of the bushes with its long tail held erect.  Since learning their song last year we have discovered that they are quiet numerous.  We now hear them almost daily, but rarely see them. They seem to prefer to stay well hidden in the brush, although their song clearly gives away their presence.  We have resorted to kind of a trick to be able to see them; we play their song from a bird App on an iPod, then they quickly appear from hiding. I’m not sure out of curiosity or a defense of territory, but they appear to lose all timidity and become very brave.